Ember CLI Cordova with Ember Simple Auth automatically signs out after a period of time in iOS

I'm currently running a project that is using Ember (2.0.1) with the Cordova platform (iOS) and using Ember Simple Auth (1.0.0) for authentication.

This issue is: you can sign in, but after an extended period of time you will be signed out automatically. Testing in the short terms works fine: I can sign in, hide the app, switch apps, close the app completely, open the app fresh, and the sign in is persisted throughout. The issue only occurs after waiting a few hours, then opening the app; at that point the user is signed out and taken to the sign in page.

I've been chasing this issue for weeks now. If anyone has any suggestions or has encountered this problem before, I'd greatly appreciate any feedback.